https://github.com/cyanheads/mcp-ts-core
Agent-native TypeScript framework for building MCP servers. Declarative definitions with auth, multi-backend storage, OpenTelemetry, and first-class support for Bun/Node/Cloudflare Workers.
https://github.com/cyanheads/mcp-ts-core
agent-native ai cloudflare-workers framework llm llm-agent mcp mcp-server model-context-protocol opentelemetry typescript
Last synced: 2 months ago
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Agent-native TypeScript framework for building MCP servers. Declarative definitions with auth, multi-backend storage, OpenTelemetry, and first-class support for Bun/Node/Cloudflare Workers.
- Host: GitHub
- URL: https://github.com/cyanheads/mcp-ts-core
- Owner: cyanheads
- License: apache-2.0
- Created: 2025-03-20T05:07:04.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2026-04-20T18:58:40.000Z (3 months ago)
- Last Synced: 2026-04-20T19:16:50.510Z (3 months ago)
- Topics: agent-native, ai, cloudflare-workers, framework, llm, llm-agent, mcp, mcp-server, model-context-protocol, opentelemetry, typescript
- Language: TypeScript
- Homepage: https://www.npmjs.com/package/@cyanheads/mcp-ts-core
- Size: 6.89 MB
- Stars: 130
- Watchers: 2
- Forks: 24
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Funding: .github/FUNDING.yml
- License: LICENSE
- Agents: AGENTS.md
Awesome Lists containing this project
README
@cyanheads/mcp-ts-core
Agent-native TypeScript framework for building MCP servers. Build tools, not infrastructure. Declarative definitions with auth, multi-backend storage, OpenTelemetry, and first-class support for Bun/Node/Cloudflare Workers.
[](./CHANGELOG.md) [](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/docs/specification/2025-11-25/changelog.mdx) [](https://modelcontextprotocol.io/) [](./LICENSE)
[](https://www.typescriptlang.org/) [](https://bun.sh/)
---
## What is this?
`@cyanheads/mcp-ts-core` is the infrastructure layer for TypeScript MCP servers. Install it as a dependency — don't fork it. You write tools, resources, and prompts; the framework handles transports, auth, storage, config, logging, telemetry, and lifecycle.
```ts
import { createApp, tool, z } from '@cyanheads/mcp-ts-core';
const greet = tool('greet', {
description: 'Greet someone by name and return a personalized message.',
annotations: { readOnlyHint: true },
input: z.object({ name: z.string().describe('Name of the person to greet') }),
output: z.object({ message: z.string().describe('The greeting message') }),
handler: async (input) => ({ message: `Hello, ${input.name}!` }),
});
await createApp({ tools: [greet] });
```
That's a complete MCP server. Every tool call is automatically logged with duration, payload sizes, memory usage, and request correlation — no instrumentation code needed. `createApp()` handles config parsing, logger init, transport startup, signal handlers, and graceful shutdown.
## Quick start
```bash
bunx @cyanheads/mcp-ts-core init my-mcp-server
cd my-mcp-server
bun install
```
You get a scaffolded project with `CLAUDE.md`, Agent Skills, and a `src/` tree ready for your tools. Infrastructure — transports, auth, storage, telemetry, lifecycle, linting — lives in `node_modules`. What's left is domain: which APIs to wrap, which workflows to expose.
Start your coding agent (Claude Code, Codex, Cursor), describe the system you want to expose, and it drives the build. The included skills cover the full cycle: `setup`, `design-mcp-server`, scaffolding, testing, `security-pass`, `release-and-publish`.
### What you get
Here's what tool definitions look like:
```ts
import { tool, z } from '@cyanheads/mcp-ts-core';
export const search = tool('search', {
description: 'Search for items by query.',
input: z.object({
query: z.string().describe('Search query'),
limit: z.number().default(10).describe('Max results'),
}),
output: z.object({ items: z.array(z.string()).describe('Search results') }),
async handler(input) {
const results = await doSearch(input.query, input.limit);
return { items: results };
},
});
```
And resources:
```ts
import { resource, z } from '@cyanheads/mcp-ts-core';
export const itemData = resource('items://{itemId}', {
description: 'Retrieve item data by ID.',
params: z.object({ itemId: z.string().describe('Item ID') }),
async handler(params, ctx) {
return await getItem(params.itemId);
},
});
```
Everything registers through `createApp()` in your entry point:
```ts
await createApp({
name: 'my-mcp-server',
version: '0.1.0',
tools: allToolDefinitions,
resources: allResourceDefinitions,
prompts: allPromptDefinitions,
});
```
It also works on Cloudflare Workers with `createWorkerHandler()` — same definitions, different entry point.
## Features
- **Declarative definitions** — `tool()`, `resource()`, `prompt()` builders with Zod schemas. `appTool()`/`appResource()` add interactive HTML UIs.
- **Unified Context** — one `ctx` for logging, tenant-scoped storage, elicitation, sampling, cancellation, and task progress.
- **Inline auth** — `auth: ['scope']` on definitions. Framework checks scopes before dispatch — no wrapper code.
- **Task tools** — `task: true` for long-running ops; framework manages create/poll/progress/complete/cancel.
- **Definition linter** — validates names, schemas, auth scopes, annotation coherence, and format-parity at startup. Standalone CLI (`lint:mcp`) and devcheck step.
- **Structured errors** — handlers throw; framework catches, classifies, and formats. Error factories (`notFound()`, `validationError()`, …) when the code matters.
- **Multi-backend storage** — `in-memory`, filesystem, Supabase, Cloudflare D1/KV/R2. Swap providers via env var; handlers don't change.
- **Pluggable auth** — `none`, `jwt`, or `oauth`. Local secret or JWKS verification.
- **Observability** — Pino logging, optional OpenTelemetry traces and metrics. Request correlation and tool metrics are automatic.
- **Local + edge** — same definitions run on stdio, HTTP (Hono), and Cloudflare Workers.
- **Tiered dependencies** — parsers, OTEL SDK, Supabase, and OpenAI are optional peers. Install what you use.
- **Agent-first DX** — ships `CLAUDE.md` with the full exports catalog so AI agents ramp up without prompting.
## Server structure
```text
my-mcp-server/
src/
index.ts # createApp() entry point
worker.ts # createWorkerHandler() (optional)
config/
server-config.ts # Server-specific env vars
services/
[domain]/ # Domain services (init/accessor pattern)
mcp-server/
tools/definitions/ # Tool definitions (.tool.ts)
resources/definitions/ # Resource definitions (.resource.ts)
prompts/definitions/ # Prompt definitions (.prompt.ts)
package.json
tsconfig.json # extends @cyanheads/mcp-ts-core/tsconfig.base.json
CLAUDE.md # Points to core's CLAUDE.md for framework docs
```
No `src/utils/`, no `src/storage/`, no `src/types-global/`, no `src/mcp-server/transports/` — infrastructure lives in `node_modules`.
## Configuration
All core config is Zod-validated from environment variables. Server-specific config uses a separate Zod schema with lazy parsing.
| Variable | Description | Default |
|:---------|:------------|:--------|
| `MCP_TRANSPORT_TYPE` | `stdio` or `http` | `stdio` |
| `MCP_HTTP_PORT` | HTTP server port | `3010` |
| `MCP_HTTP_HOST` | HTTP server hostname | `127.0.0.1` |
| `MCP_AUTH_MODE` | `none`, `jwt`, or `oauth` | `none` |
| `MCP_AUTH_SECRET_KEY` | JWT signing secret (required for `jwt` mode) | — |
| `STORAGE_PROVIDER_TYPE` | `in-memory`, `filesystem`, `supabase`, `cloudflare-d1`/`kv`/`r2` | `in-memory` |
| `OTEL_ENABLED` | Enable OpenTelemetry | `false` |
| `OPENROUTER_API_KEY` | OpenRouter LLM API key | — |
See [CLAUDE.md](CLAUDE.md) for the full configuration reference.
## API overview
### Entry points
| Function | Purpose |
|:---------|:--------|
| `createApp(options)` | Node.js server — handles full lifecycle |
| `createWorkerHandler(options)` | Cloudflare Workers — returns `{ fetch, scheduled }` |
### Builders
| Builder | Usage |
|:--------|:------|
| `tool(name, options)` | Define a tool with `handler(input, ctx)` |
| `resource(uriTemplate, options)` | Define a resource with `handler(params, ctx)` |
| `prompt(name, options)` | Define a prompt with `generate(args)` |
| `appTool(name, options)` | Define an MCP Apps tool with auto-populated `_meta.ui` |
| `appResource(uriTemplate, options)` | Define an MCP Apps HTML resource with the correct MIME type and `_meta.ui` mirroring for read content |
### Context
Handlers receive a unified `Context` object:
| Property | Type | Description |
|:---------|:-----|:------------|
| `ctx.log` | `ContextLogger` | Request-scoped logger (auto-correlates requestId, traceId, tenantId) |
| `ctx.state` | `ContextState` | Tenant-scoped key-value storage |
| `ctx.elicit` | `Function?` | Ask the user for input (when client supports it) |
| `ctx.sample` | `Function?` | Request LLM completion from the client |
| `ctx.signal` | `AbortSignal` | Cancellation signal |
| `ctx.notifyResourceUpdated` | `Function?` | Notify subscribed clients a resource changed |
| `ctx.notifyResourceListChanged` | `Function?` | Notify clients the resource list changed |
| `ctx.progress` | `ContextProgress?` | Task progress reporting (when `task: true`) |
| `ctx.requestId` | `string` | Unique request ID |
| `ctx.tenantId` | `string?` | Tenant ID (from JWT or `'default'` for stdio) |
### Subpath exports
```ts
import { createApp, tool, resource, prompt } from '@cyanheads/mcp-ts-core';
import { createWorkerHandler } from '@cyanheads/mcp-ts-core/worker';
import { McpError, JsonRpcErrorCode, notFound, serviceUnavailable } from '@cyanheads/mcp-ts-core/errors';
import { checkScopes } from '@cyanheads/mcp-ts-core/auth';
import { markdown, fetchWithTimeout } from '@cyanheads/mcp-ts-core/utils';
import { OpenRouterProvider, GraphService } from '@cyanheads/mcp-ts-core/services';
import { validateDefinitions } from '@cyanheads/mcp-ts-core/linter';
import { createMockContext } from '@cyanheads/mcp-ts-core/testing';
import { fuzzTool, fuzzResource, fuzzPrompt } from '@cyanheads/mcp-ts-core/testing/fuzz';
```
See [CLAUDE.md](CLAUDE.md) for the complete exports reference.
## Examples
The `examples/` directory contains a reference server consuming core through public exports, demonstrating all patterns:
| Tool | Pattern |
|:-----|:--------|
| `template_echo_message` | Basic tool with `format`, `auth` |
| `template_cat_fact` | External API call, error factories |
| `template_madlibs_elicitation` | `ctx.elicit` for interactive input |
| `template_code_review_sampling` | `ctx.sample` for LLM completion |
| `template_image_test` | Image content blocks |
| `template_async_countdown` | `task: true` with `ctx.progress` |
| `template_data_explorer` | MCP Apps with linked UI resource via `appTool()`/`appResource()` builders |
## Testing
```ts
import { createMockContext } from '@cyanheads/mcp-ts-core/testing';
import { myTool } from '@/mcp-server/tools/definitions/my-tool.tool.js';
const ctx = createMockContext({ tenantId: 'test-tenant' });
const input = myTool.input.parse({ query: 'test' });
const result = await myTool.handler(input, ctx);
```
`createMockContext()` provides stubbed `log`, `state`, and `signal`. Pass `{ tenantId }` for state operations, `{ sample }` for LLM mocking, `{ elicit }` for elicitation mocking, `{ progress: true }` for task tools.
### Fuzz testing
Schema-aware fuzz testing via `fast-check`. Generates valid inputs from Zod schemas and adversarial payloads (prototype pollution, injection strings, type confusion) to verify handler invariants.
```ts
import { fuzzTool } from '@cyanheads/mcp-ts-core/testing/fuzz';
const report = await fuzzTool(myTool, { numRuns: 100 });
expect(report.crashes).toHaveLength(0);
expect(report.leaks).toHaveLength(0);
expect(report.prototypePollution).toBe(false);
```
Also exports `fuzzResource`, `fuzzPrompt`, `zodToArbitrary`, and `ADVERSARIAL_STRINGS` for custom property-based tests.
## Documentation
- **[CLAUDE.md](CLAUDE.md)** — Framework reference: exports catalog, patterns, Context interface, error codes, auth, config, testing. Ships in the npm package.
- **[CHANGELOG.md](CHANGELOG.md)** — Version history
## Development
```bash
bun run rebuild # clean + build (scripts/clean.ts + scripts/build.ts)
bun run devcheck # lint, format, typecheck, MCP defs, audit, outdated
bun run lint:mcp # validate MCP definitions against spec
bun run test:all # vitest (unit + integration)
```
## Contributing
Issues and pull requests welcome. Run checks before submitting:
```bash
bun run devcheck
bun run test:all
```
## License
Apache 2.0 — see [LICENSE](./LICENSE).
---